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In this paper we put forward the idea that the comoving Hubble horizon undergoes multiple stages of contraction (a.k.a. inflationary phase) and expansion. The observable inflation, that produces the CMB anisotropies and generates primordial…

High Energy Physics - Theory · Physics 2020-05-06 Mahdi Torabian

In the standard model of cosmology, the Universe began its expansion with an anomalously low entropy, which then grew dramatically to much larger values consistent with the physical conditions at decoupling, roughly 380,000 years after the…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-22 Fulvio Melia

In this work we analyse in detail the possibility of using small and intermediate-scale gravitational wave anisotropies to constrain the inflationary particle content. First, we develop a phenomenological approach focusing on anisotropies…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-09 Ema Dimastrogiovanni , Matteo Fasiello , Ameek Malhotra , P. Daniel Meerburg , Giorgio Orlando

A model of magnetic universe based on nonlinear electrodynamics has been introduced by Kruglov. This model describes an early inflation era followed by a radiation era. We show that this model is related to our model of universe based on a…

General Relativity and Quantum Cosmology · Physics 2024-06-04 Pierre-Henri Chavanis

There have been persistent suggestions, based on several diverse data sets, that the cosmic expansion is not exactly isotropic. It is not easy to develop a coherent theoretical account of such a ``Hubble anisotropy'', for, in standard…

General Relativity and Quantum Cosmology · Physics 2025-09-09 Brett McInnes

This paper shows how increased entropy values from an initially low big bang level can be measured experimentally by counting relic gravitons. Furthermore the physical mechanism of this entropy increase is explained via analogies with…

General Physics · Physics 2009-05-08 A. W. Beckwith

There is sufficient amount of internal evidence in the nature of gravitational theories to indicate that gravity is an emergent phenomenon like, e.g, elasticity. Such an emergent nature is most apparent in the structure of gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 T. Padmanabhan

Using numerical solutions of the full Einstein field equations coupled to a scalar inflaton field in 3+1 dimensions, we study the conditions under which a universe that is initially expanding, highly inhomogeneous and dominated by gradient…

High Energy Physics - Theory · Physics 2016-09-07 William E. East , Matthew Kleban , Andrei Linde , Leonardo Senatore

We summarize three recent efforts to constrain the first few moments of cosmic creation before and during the epoch of inflation. We consider two means to explain a slight dip in the power spectrum of the cosmic microwave background for…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-19 G. J. Mathews , M. R. Gangopadhyay , P. Garnavich , B. Rose , K. Ichiki , T. Kajino , D. Yamazaki

We first present open questions related to the foundations of thermodynamics and statistical physics. We then argue that in principle one can not have "closed systems", and that a universal background should exist. We propose that the…

Condensed Matter · Physics 2009-10-31 Eshel Ben-Jacob , Ziv Hermon , Alexsander Shnirman

Current astronomical observations are successfully explained by the present cosmological paradigm based on the concordance model ($\Lambda_0$CDM + Inflation). However, such a scenario is composed of a heterogeneous mix of ingredients for…

General Relativity and Quantum Cosmology · Physics 2018-08-29 J. A. S Lima , Douglas Singleton

In the standard cosmological model, the temperature anisotropy of the cosmic microwave background is interpreted as variation in the gravitational potential at the point of emission, due to the emitter being embedded in a region ${\cal C}$…

Astrophysics · Physics 2007-05-23 Richard Lieu

We look at the transition to the semiclassical behaviour and the decoherence process for the inhomogeneous perturbations in the inflationary universe. Two different decoherence mechanisms appear: one dynamical, accompanied with a…

General Relativity and Quantum Cosmology · Physics 2014-11-17 I. L. Egusquiza , A. Feinstein , M. A. Perez Sebastian , M. A. Valle Basagoiti

Standard calculations suggest that the entropy of our universe is dominated by black holes, whose entropy is of order their area in Planck units, although they comprise only a tiny fraction of its total energy. Statistical entropy is the…

High Energy Physics - Theory · Physics 2009-09-17 Paul Frampton , Stephen D. H. Hsu , Thomas W. Kephart , David Reeb

In this work, we outline a new general relativistic cosmology. In this cosmology, the universe originates in the infinite past from sparsely distributed neutral matter and ends in the infinite future as a hot, relativistic plasma. The…

Astrophysics · Physics 2007-05-23 Sanjay M. Wagh

The mechanism for triggering the universe inflation could be that at very early periods the time variable was discrete instead of smooth. Alternatively, and perhaps equivalently, it could be the consequence that the metrics of the early…

High Energy Physics - Theory · Physics 2016-12-28 Laurent Baulieu

Over the past three years we have determined the basic features of our Universe. It is spatially flat; accelerating; comprised of 1/3 a new form of matter, 2/3 a new form of energy, with some ordinary matter and a dash of massive neutrinos;…

Astrophysics · Physics 2008-11-26 Michael S. Turner

We discuss some current problems in the relationship between elementary particle physics and gravitation, i.e., in the subject investigated by Prof.~K.~P.~Staniukovich half a century ago. Specifically, the inflationary stage of the Universe…

History and Philosophy of Physics · Physics 2016-06-17 V. M. Mostepanenko

Measurements of CMB anisotropy and, more recently, polarization have played a very important role allowing precise determination of various parameters of the `standard' cosmological model. The expectation of the paradigm of inflation and…

Astrophysics · Physics 2008-11-26 Tarun Souradeep

Inflationary cosmology provides a natural mechanism for the generation of primordial perturbations which seed the formation of observed cosmic structure and lead to specific signals of anisotropy in the cosmic microwave background…

Astrophysics · Physics 2011-07-19 Salman Habib , Andreas Heinen , Katrin Heitmann , Gerard Jungman
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